Theory

What is Calibration ?

In order to measure the position of a marker in space, it must be viewed by two or more cameras whose locations and orientations are known.  Calibration or camera system calibration is performed to determine the location and orientation( external camera parameters ) of each camera.  Because the calibration procedure determines the cameras' locations and orientations, the process should be repeated each time the camera may have been disturbed.

MaxTRAQ uses dynamic wand calibration.  A reference structure with 4 markers and a wand with 2 markers are needed to dynamic wand calibration. Reference structure will be used to line up the global coordinate system and the wand will be used to scale the coordinate system.

In Addition to calculating the external camera parameters, the calibration process also calculates the internal camera parameters and creates linearization table.  This will ensure that the highest possible accuracy for the current setup is achieved. It is also important to note that you will not get any 3D data outside the linearized volume.  For measurement setups where it may be hard to move the wand around the entire area, you can do a calibration outside the actual measurement area where you are able to move the wand around without any problems to create linearization tables.  You will then need to go to the Tools --> Options and select Lock Linearization Tables to make sure that the linearization tables will not be over written by a new calibration.